Robot and method for controlling the robot

ABSTRACT

A robot includes a first axle and a second axle. A first axle housing includes a first transversal axle connected to a rigid structure by a hinge having a first degree of freedom in rotation around a first axis which is vertical and a second degree of freedom in rotation around a second axis which is perpendicular to the first axis and to a first transversal axis. The first transversal axle is equipped on either side with a motor, each motor having a stator and a rotor rotatably mounted to a respective wheel to provide steering and propulsion functions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-Part of: international PCT PatentApplication Serial No. PCT/EP2019/058942 filed on Apr. 9, 2019, PCTPatent Application Serial No. PCT/EP2018/058990 filed Apr. 9, 2018, PCTPatent Application Serial No. PCT/EP2018/058989 filed Apr. 9, 2018, andPCT Patent Application Serial No. PCT/EP2018/058987 filed Apr. 9, 2018.PCT Patent Application Serial No. PCT/EP2019/058942 claims priority toPCT Patent Application Serial No. PCT/EP2018/058991 filed on Apr. 9,2018. All of the above applications are incorporated by referenceherein.

TECHNICAL FIELD

The invention relates to a robot having a chassis and a method forcontrolling the robot. It also relates to a robot having a chassis and afree rear axle housing with two axes of rotation with respect to thechassis. It also relates to a connecting module for a brush cutter, edgetrimmer or the like, comprising a chassis and a cutting module. It alsorelates to a cutting head for a brush cutter, edge trimmer or the like.More precisely, it relates to a cutting head comprising a comb and aplurality of motorized disks aligned transversely, rotatably mounted onthe comb, wherein the motorized disk support a plurality of articulatedblades on the disk and adapted to extend radially relative to therotation axis of said disks under the effect of the centrifugal force.

SUMMARY

An object of the invention is, in particular, to provide a robot with alow propulsion consumption. Another object of the invention is, inparticular, to provide a robot having a chassis and a free rear axlehousing with two axes of rotation with respect to the chassis whichensure a longer life of the chassis as compared to the known robothaving a chassis and a free rear axle housing with two axes of rotationof the previous art. Another object of the invention is to provide arobot a chassis and a free rear axle housing with two axes of rotationwith respect to the chassis which is more suitable for its use in theagricultural fields as compared to the known robot having a chassis anda free rear axle housing with two axes of rotation of the previous art.

In a configuration such as vineyard, a park, a photovoltaic field, manyobstacles are present (vines, pegs, clods, potholes, slope,counter-slope, abandoned objects, etc.). A robot in such a configurationmust face all the obstacles without ever being “jammed” and thus forcedto stop his automatic work. It should be noted that given a very lowspeed of movement of the robot and a low weight of the robot, thesecontacts have no effect on the vines.

The best solution for cutting the grass closer to the grass is to comeinto contact with the obstacle. Therefore, the robot is not configuredto avoid the obstacle but to detect it as quickly as possible. In theseagricultural fields, the number of obstacles per unit area, andtherefore the number of contacts between the robot and these obstaclesper unit of time can be as important as one obstacle every 12 seconds ina vineyard planted at 6600 feet per hectare (plus 20% of stakes), at aspeed of 350 m/h.

The advantages of a front-cutting module are known, such as being usedin difficult access places. To the intent to cut all the grass on thecutting front, and because two blades of two consecutive cutting disksshould not meet, two consecutive motorized disks are placed on twoparallel, but different, plans. Therefore two blades of two consecutivecutting disks do not meet.

Designing such a cutting head with different plans makes the productionof said cutting head expensive and complicated. Also, a same grass maybe cut by two blades of different motorized disks, therefore being cutat two different levels. To this effect, according to a first aspect ofthe invention, the invention relates to, robot comprising a first axleand a second axle, the first axle housing comprising a first transversalaxle connected to a rigid structure by a hinge having a first degree offreedom in rotation around a first axis which is vertical and a seconddegree of freedom in rotation around a second axis which isperpendicular to the first axis and to the first transversal axis, andthe axle of the first transversal axle being equipped on either sidewith a motor, each motor having a stator part intended for to be fixedto the first transversal axle and a rotor part to be rotatably mountedto a respective wheel to provide steering and propulsion functions.

The robot might be further arranged to receive electronic controlsconfigured to control each of the motors fitted to said axle housing.According to further non-limitative features of the invention, eithertaken alone or in all technically feasible combinations:

-   -   the electronic controls are configured to drive each motor        independently;    -   the hinge is placed on the center of the transversal axis;    -   the center of gravity of the robot is located between the four        wheels;    -   the chassis is shell that goes down between the two axles to        lower the center of gravity;    -   the rigid structure is a shell;    -   the robot comprises a unique battery;    -   the robot comprises a frontal cutting module place between two        wheels, either on the front or on the rear of the robot, and the        two other wheels are steering wheels;    -   the 4 wheels are driving wheels;    -   the electronic controls are configured to implement a robot        moving strategy towards a predetermined destination point by        minimization of the distance to the predetermined destination        point, the strategy being locally random;    -   the robot comprises means for detecting an obstacle.    -   the means for detecting the obstacle are configured to detect an        obstacle by combination of two or more of the following        parameters:        -   counter electromotive force of one of the motor;        -   differential of inertial components for detection of            acceleration and/or acceleration variation;        -   angular sensor of steering wheels;        -   geographical localization;    -   the electronic controls are configured to invert the direction        of movement of the robot when an obstacle is detected.    -   the robot comprises a frontal cutting module place between two        wheels, and, in the event that the obstacle detected is on the        side of the cutting tool, the electronic controls are configured        to stop the robot and to select a steering direction to        circumvent the obstacle before inverting the direction of the        movement;    -   the robot comprises an angular sensor of the angle formed by the        transverse axis relative to the frame, said angular sensor        comprising a flag fixed in rotation with the first axis and a        rangefinder to measure the distance between the flag and a fixed        point of the rigid structure.

Preferably, the axle housing is rotatable around two axes of rotationwith respect to a chassis of the robot. In an embodiment, the rear axleis a free rear axle with two axes of rotation with respect to thechassis, which comprises a stop device for circumscribing in space thedisplacements of the rear axle. Preferably, the stop device comprises aplate of rectangular shape defining a main plane and a center of therectangular shape.

According to an embodiment, the plane orthogonal to the main plane andextending in the longitudinal direction of the plate and passing throughthe center of the rectangle is a plane of symmetry of the stop device.Preferably, the plane orthogonal to the main plane and extending in thedirection transverse to the longitudinal direction of the plate andpassing through the center of the rectangle is a plane of symmetry ofthe stop device. For example, four screw passages may be formed at thecorners of a rectangle centered on the center of the plate.

On an embodiment, four damper passages are formed in the plate at thecorners of a rectangle centered on the center of the plate. Preferably,the stop device has four stops distributed symmetrically with respect tothe two planes of symmetry of the stop device. For example, a stop has aright-angled triangle section whose right angle is disposed at one endof the rectangle forming the plate, one side of the right angle beingoriented in the longitudinal direction of the plate, the other side theright angle being directed in the direction of a longitudinal planeperpendicular to the main plane. Preferably, a vertical sectiontransverse to the longitudinal direction of the plate, the plate ishollowed out on a lower central portion to form a “H” which upper leftand right interior angles are provided with fillets.

The invention also relates to a method of controlling a robot comprisingan axle housing arranged to receive two wheels and intended to providesteering and propulsion functions of said two wheels, said methodcomprising to control two motors which are housed in said axle housing,on either side, each motor having a stator part intended for to be fixedto the axle housing and a rotor part to be rotatably mounted to saidwheel, said robot being further arranged to receive control electronicsconfigured to control each of the motors fitted to said axle housing.According to another aspect, the invention relates to a connectingmodule for a brush cutter, edge trimmer or the like, comprising achassis and a cutting module, said module being intended to be connectedto said chassis, on the one hand, by flexible damping elements and, onthe other hand, fixed to said cutting module, said module being equippedwith position sensors of said cutting module with respect to saidchassis. Preferably, the connection between said connecting module andthe chassis has the degrees of freedom, around the pitch and roll axis,according to the mowing direction of the brush cutter, edge trimmer orthe like. The position sensors may comprise an electronic inertialmeasurement unit.

According to a second aspect of the invention, the invention relates toa brush cutter, edge trimmer or the like comprising a connecting moduleas claimed according to the previous aspect of the invention, or one ormore of its improvement elements. Preferably, the chassis comprises aprocessing unit and a controller, the processing unit being configuredto detect obstacle by using data provided by the position sensors and tosend orders to the controller. In an embodiment, the chassis may furthercomprise sensors fixed onto it and the processing unit may also beconfigured to detect obstacle by using data provided by the saidsensors.

The sensors may comprise a torque sensor for each of the wheels. Thesensors may comprise a geographical position system. The processing unitmay be also configured to detect obstacle by using data provided by thecontroller.

According to a fourth aspect of the invention, a method of detecting anobstacle is provided, comprising the use of a connecting moduleaccording to the invention, or one or more of its improvement elements,or the use of a brush cutter, edge trimmer or the like, according to thesecond aspect of the invention, or one or more of its improvementelements. The invention relates, according to an aspect of theinvention, to a cutting head for a brush cutter, edge trimmer or thelike, comprising a front cutting module comprising a comb havinglongitudinally extending teeth and a plurality of N motorized diskaligned transversely, at least one disk of said plurality of motorizeddisk being rotatably mounted on the comb around a rotation axis, whereinat least one disk of the plurality of motorized disk supports aplurality of articulated blades over the said disk and adapted to extendradially relative to the rotation axis of said disk under the effect ofthe centrifugal force, said comb having a width at least equal to Ntimes the cut diameter of the cut area of a motorized disk, wherein atleast two consecutive motorized disks of said plurality of motorizeddisks are coplanar and wherein the distance between the axis of said atleast two consecutive motorized disks is between 1 and 1,2 times the cutdiameter of a disk of said at least two consecutive motorized disks.

Such a cutting head is easier to make than the one according the priorart. Such a cutting head avoid cutting twice the same grass. Preferably,each disk of said plurality of motorized disk is rotatably mounted onthe comb around a rotation axis.

Preferably, each disk of the plurality of motorized disk supports aplurality of articulated blades over the said disk and adapted to extendradially relative to the rotation axis of said disk under the effect ofthe centrifugal force. A blade may be mounted rotatably on the disk onwhich said blade is articulated. The cut area of a disk is the area cutby all the blades articulated on said disk when the blades are in theextended position. The cut area of the front cutting module is the unionof each of the cut area of the motorized disk.

Preferably, each disk of said plurality of motorized disk is driven inrotation by a rotor of a motor, said motor having a stator secured onthe front cutting module. Said motor may drive only one disk. Forexample, such of motor may be a stepper motor.

In an embodiment, the comb may have interposed teeth extendinglongitudinally along a central axis perpendicular to the axes of twoconsecutive motorized disks. A comb according to this embodiment doesnot to leave an uncut grass between the two disks. Preferably, the combhas teeth whose ends extend in an arcuate area.

Advantageously, the comb may have a conformation comprising a passageforming a path for discharging grass cut by the articulated blades. Acomb according to this embodiment keeps the teeth clean and not stuck bythe cutting grass. The passage may be a means for cutting the grass in areverse direction.

The rounded shape of the outer tooth might allow to slide on the vinewithout damaging it. Teeth might help guiding the grass for cutting. Theshape of the comb might be designed to protect the cutting discs, sothat only the blade is in contact with the grass and/or so that the discnever comes into contact with pebbles, branches, . . . . According to anaspect of the invention, coupling means are provided with a cutting headaccording to the invention, or one or more of its improvement elements.

According to an aspect of the invention, a scooter is provided with acutting head according to the invention, or one or more of itsimprovement elements. According to an aspect of the invention, a segwayis provided with a cutting head according to the invention, or one ormore of its improvement elements. According to a fifth aspect of theinvention, a robot is provided with a cutting head according to theinvention, or one or more of its improvement elements.

BRIEF DESCRIPTION OF THE DRAWINGS

Many other features and advantages of the present invention will becomeapparent from reading the following detailed description, whenconsidered in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a mowing robot according to theinvention;

FIG. 2 is a perspective view of the bottom of the robot of FIG. 1;

FIG. 3 is another perspective view of FIG. 1;

FIG. 4 is a perspective view of the bottom of the robot of FIG. 1;

FIG. 5 is a perspective view of the rear axle of the robot of FIG. 1;

FIG. 6 is a perspective view of a stop element of the rear axle of FIG.5;

FIG. 7 is a perspective view and a down section of a stop element ofFIG. 6;

FIG. 8 is a multi-view projection, front, top and bottom, left andright, of the stop element of FIG. 6;

FIG. 9 is a perspective view, from the top of the robot of FIG. 1;

FIG. 10 is another perspective view of a mowing robot comprising aconnecting module;

FIG. 11 is a cutaway drawing of FIG. 11;

FIG. 12 is a front view of FIG. 11;

FIG. 13 is a left side view of FIG. 11;

FIG. 14 is a top view of FIG. 11;

FIG. 15 is a schematic representation of the mowing robot of FIG. 11;

FIG. 16 is a perspective view of another embodiment of a mowing robotcomprising a connecting module;

FIG. 17 is a schematic representation of an embodiment of a cutting headaccording to the invention;

FIG. 18 is a schematic representation of a scooter according to anembodiment of the invention;

FIG. 19 is a schematic representation of a segway according to anembodiment of the invention;

FIG. 20 is a schematic representation of a robot according to anembodiment of the invention;

FIG. 21 is a schematic representation of another scooter according to anembodiment of the invention; and

FIG. 22 is a schematic representation of another embodiment of a cuttinghead according to the invention.

DETAILED DESCRIPTION

The embodiments described hereinafter being in no way limiting, it ispossible in particular to consider variants of the invention comprisingonly a selection of characteristics described, subsequently isolatedfrom the other characteristics described, if this selection ofcharacteristics is sufficient to confer a technical advantage or todifferentiate the invention from the state of the art. This selectioncomprises at least one characteristic, preferably functional withoutstructural details, or with only a part of the structural details ifthis part only is sufficient to confer a technical advantage or todifferentiate the invention from the prior art. The same referencenumbers are used for identical elements or elements achieving the samefunction in the different embodiments of the invention that will bedescribed.

FIG. 1 is a perspective view of a mowing robot 1 according to theinvention. The mowing robot 1 is autonomous in energy and comprises aunique battery. The mowing robot 1 comprises a chassis 2, which is arigid structure, preferably a shell, which is linked to a front axlehousing 100 and to a rear axle housing 200.

The front axle housing 100 is fixed to the chassis 2. The front axlehousing 100 is linked to two front wheels 102 and 104, which arerotating around the front axle housing 3. At the end of the front axlehousing 100 at the wheel 102, the front axle housing 100 comprises amotor 110.

The stator part 112 of the motor is fixed to the front axle housing 100via a radially external part of a bearing 120 (no shown on the figures).The wheel 102 is fixed to a rotatory part 114 of the motor 110 via theradially internal part of the bearing 120. At the end of the front axlehousing 100 at the wheel 104, the front axle housing 100 comprises amotor 130.

The stator part 132 (not shown on the figures) of the motor is fixed tothe front axle housing 100 via a radially external part of a bearing 140(not shown on the figures). The wheel 104 is fixed to a rotatory part134 (not shown on the figures) of the motor 130 via the radiallyinternal part of the bearing 120. A cable duct 150 is provided to passelectrical wires, which are not shown in the figures, connected to themotors 110 and 130.

The rear axle housing 200 is linked to two rear wheels 202 and 204,which are rotating around the front axle housing 3. The rear axlehousing 200 defines a first transversal axle. At the end of the rearaxle housing 200 at the wheel 202, the front axle housing 200 comprisesa motor 210.

The stator part 212 (not shown on the figures) of the motor is fixed tothe rear axle housing 200 via a radially external part of a bearing 220(not shown on the figures). The wheel 202 is fixed to a rotatory part214 (not shown on the figures) of the motor 210 via the radiallyinternal part of the bearing 220. At the end of the rear axle housing200 at the wheel 204, the front axle housing 100 comprises a motor 230.

The stator part 232 (not shown on the figures) of the motor is fixed tothe front axle housing 200 via a radially external part of a bearing 240(not shown on the figures). The wheel 204 is fixed to a rotatory part234 (not shown on the figures) of the motor 230 via the radiallyinternal part of the bearing 220. Each motor has its stator part fixedto the first transversal axle and its rotor part (brush, brushless)rotatably mounted to a respective wheel (202, 204) to provide steeringand propulsion functions. A cable duct 250 is provided to passelectrical wires connected to the motors 210 and 230 which are not shownin the figures.

The rear axle housing 200 is pivotally mounted on a steering pivot 400around a horizontal axis, which is perpendicular to the longitudinalaxis of the rear axle housing 200. The steering pivot 400 is pivotallymounted on a blocking device 500 around a vertical axis. Thus, the rearaxle is connected to the rigid structure 2 by a hinge having a firstdegree of freedom in rotation around a first axis—the verticalaxis—which is vertical and a second degree of freedom in rotation arounda second axis—the horizontal axis—which is perpendicular to the firstaxis and to the transversal axis. The hinge is placed on the center ofthe transversal axis.

The shell 2 goes down between the two axles to lower the center ofgravity. The center of gravity of the robot 2 is located between thefour wheels 102, 104, 202, 204. The four wheels 102, 104, 202, 204 aredriving wheels.

The robot 2 comprises a frontal cutting module located between twowheels 102, 104, on the front of the robot. However, only the two wheels102, 104, which are located opposite from the frontal cutting module aresteering wheels. This is useful to maximize the width of the fontalcutting module. The wheels between which the cutting module is locatedare only driving wheels, not steering wheels.

The blocking device 500 is adapted to circumscribe in space thedisplacements of the rear axle housing 200. The blocking device 500comprises four damping devices 550, as rubber. The damping devices helpto ensure long life for the blocking device. The blocking device 500device is fixed on the chassis 2. Therefore, the chassis 2 can rotatearound the forward driving direction and around the vertical direction.

As it might better seen on FIG. 9, the steering pivot 400 is extended bya tube 600 opening into the chassis 2. The tube 600 forms cable duct 600provided to pass electrical wires, which are not shown in the figures,connected to the motors 210 and 230. The tube 600 is rotationallyintegral with a flag 602.

The chassis 2 is further provided with a sensor 604 for the angularposition of the flag 602. In the example shown in FIG. 9, the sensor 604of the angular position of the flag 602 is a rangefinder. Therangefinder 604 emits an infrared wave that is reflected on the flag602, linked to the axis of the rear axle.

The value received by the rangefinder changes according to the distanceof the reflective object which is the flag. When the rear axle movesangularly around the vertical axis, the distance of the flag from therangefinder changes. We can therefore measure the angular position ofthe rear train. Therefore, the motors 210, 230, are controlled by acontroller 300 which is fixed to the chassis 2.

The data provided by the sensor of the angular position of the flag 602are sent to the controller 300. Therefore, the robot comprises anangular sensor of the angle formed by the transverse axis relative tothe frame, the angular sensor comprising the flag 602 fixed in rotationwith the first axis and a rangefinder 604 to measure the distancebetween the flag and a fixed point of the rigid structure 2. Therefore,the angular position of the free rear train is known and the robot mightbe driven.

The controller 300 controls the motors 210 and 230, independently, inorder to change the direction of the mowing robot 1, by pivoting thechassis 2 around the rear axle housing. Therefore, the rear axle housingis a drive and steering axle. In order to rotate the chassis 2 aroundthe rear axle housing, the controller 300 is configured to control themotors 210 and 230 with two different speed rotations.

The motors 110, 130, are also controlled, independently, by thecontroller 300. In this embodiment, the controller 300 is configured tocontrol the motors 110 and 130 with a same speed rotation. Therefore,the front axle housing is a drive axle but not a steering axle.

The electronic controls 300 are configured to implement a robot movingstrategy towards a predetermined destination point by minimization ofthe distance to the predetermined destination point, the strategy beinglocally random. The moving strategy might consider the distance to theborder of the fields on which is placed the robot. To this end, therobot might consider the geolocation border and the accuracy of the GPS.

The moving strategy might be an opportunistic random displacementlocally, mainly opportunistic. The moving strategy might implementderogations to the minimization, by learning derogations by historicaldata. The moving strategy might implement corner strategy by inversionof changing the predetermined destination point after a given period.

The robot might comprise comprising means for detecting an obstacle. Onthe embodiment, the electronic controls form part of the means fordetecting an obstacle. The electronic controls are further configured todetect an obstacle by combination of two or more of the followingparameters:

-   -   counter electromotive force of one of the motors;    -   differential of inertial components (the robot might comprise an        IMU or accelerometers, compass and gyroscopic sensors) for        detection of acceleration and/or acceleration variation        [inconvenience: very noisy];    -   angular sensor of steering wheels known from the flag 602 and        the rangefinder 604,    -   geographical localization (for example GPS).

The electronic controls 300 might be configured to invert the directionof movement of the robot when an obstacle is detected. In the event thatan obstacle detected is on the side of the cutting tool, the electroniccontrols are configured to stop the robot and to select a steeringdirection to circumvent the obstacle before inverting the direction ofthe movement.

The blocking device 500 might be better seen on FIGS. 6 and 7. Thedevice 500 comprises a plate 502 of rectangular shape centered around avertical axis z. The plate has a main plane extending in both directionsof its rectangular shape.

The device 500 comprises on one side of the plate 502 with respect tothe z axis, a cylinder 504 of annular section. The outer diameter of theannular section is smaller than the width of the plate 502. The insidediameter of the annular section is sufficient to allow a passage ofelectric cable.

As shown in FIG. 7b , the plate 502 has at its center a recess 508 whichcooperates with the recess of the cylinder 504 of the annular section.The recess of 508 is of the same diameter as the inside diameter of theannular section. Four passages 510 are formed at the corners of arectangle centered on the center of the plate 502. The passages 510allow the fixing by screw and bolt of the plate 502 on the frame 2.

Four other passages 512 are formed in the plate at the corners of arectangle centered on the center of the plate 502. The passages 512allow the insertion of the damping device 550 which opens on theopposite side to the cylinder 504 with respect to the z axis.

The plane orthogonal to the main plane and extending in the longitudinaldirection of the plate and passing through the middle of the width ofthe rectangle forming the plate is a plane of symmetry of the device500. The plane orthogonal to the main plane and extending in thedirection transverse to the longitudinal direction of the plate andpassing through the middle of the length of the rectangle forming theplate is a plane of symmetry of the device 500. On the side of the plate502 opposite the cylinder 504 with respect to the axis z, the device 500has four stops 506 distributed symmetrically with respect to the twoplanes of symmetry of the device 500.

More specifically, a stop 506 has a right-angled triangle section whoseright angle is disposed at one end of the rectangle forming the plate502, one side of the right angle being oriented in the longitudinaldirection of the plate, the other side the right angle being directed inthe direction of the axis z opposite to the cylinder 504. The stop hasan extension of the right triangle in the direction of the width of therectangle forming the plate 502.

FIG. 8 shows the device 500 in a multi-view projection, front, top andbottom, left and right, according to the US third-angle projection. In avertical section transverse to the longitudinal direction of the plate502, the plate 502 is hollowed out on a lower central portion to form a“H” which upper left and right interior angles are provided withfillets.

FIG. 10 a perspective view of the mowing robot 1 comprising the chassis2 suspended on wheels 3, and a cutting module 4. The mowing robot 1 alsocomprise a connecting module 5. The connecting module 5 is connected tothe chassis 2, for example by flexible damping elements 6 (see FIG. 11),such as silent blocks.

The connecting module 5 is fixed to the cutting module 4, for example bymeans of screws (not shown). As illustrated on FIG. 12, which is aschematically front view of FIG. 1, the connecting module might be in aposition which is rotated around a longitudinal axis (according to themowing direction) of the mowing robot 1. On subFIG. 12 a, the right sideof the cutting module 4 (according to the mowing direction) is raisedwhile the left side of the cutting module 4 is lowered. On subFIG. 12 b,both side of the cutting module 4 are at the same level. On subFIG. 12c, the left side of the cutting module 4 (according to the mowingdirection) is lowered while the right side of the cutting module 4 israised.

As illustrated on FIG. 13, which is a schematically side view of FIG. 1,taken on the left side of the mowing robot according to the mowingdirection, the connecting module might be in a position which is rotatedaround a transverse axis (according to the mowing direction) of themowing robot 1. On subFIG. 13 a, both side of the cutting module 4 areat the same level. On subFIG. 13 b, the front side of the cutting module4 (according to the mowing direction) is raised while the rear side ofthe cutting module 4 is lowered. On subFIG. 13 c, the front side of thecutting module 4 (according to the mowing direction) is lowered whilethe rear side of the cutting module 4 is raised.

As illustrated on FIG. 14a , which is a schematically top view of FIG. 1of the mowing robot, the connecting module might be in a position whichis rotated around a vertical axis of the mowing robot 1. On subFIG. 14b, the cutting module 4 is in a nominal direction. On subFIG. 14 c, thecutting module 4 is turned around the vertical axis according to anegative angle. On subFIG. 14 c, the cutting module 4 is turned aroundthe vertical axis according to a positive angle.

The connection between the connecting module 5 and the chassis 2 has sixdegrees of freedom: three rotations are shown on FIGS. 3 to 5 while 3translations are allowed due to the use of damping elements connectingthe cutting module 4 to the chassis 2. As schematically represented onFIG. 15 which is a schematic representation of the mowing robot of FIG.10, the connecting module 5 is equipped with position sensors 7 of saidcutting module with respect to said chassis. More specifically, theposition sensors 7 comprise an electronic inertial measurement unitcalled IMU (for the English “Inertial Measurement Unit”). The IMUcomprises a gyroscope, an accelerometer.

The mowing robot 1 might comprise a processing unit 8 and a controller9. The information provided by the position sensors 7 might besufficient to detect an obstacle. The processing unit 8 might beconfigured to detect obstacle by using data provided by the positionsensors 7. The processing unit 8 might be configured to send orders 10to the controller 9. In the embodiment illustrated on FIG. 15, thechassis further comprise sensors 11 fixed onto it.

The connecting module 5 is connected to the chassis 2 by a deformableconnection of rubber type. In case of encounter of the cutting head withan obstacle, the silent blocs 6 absorb a part of the energy of theshock, and allows a local deformation between the connecting module 5and the chassis 2. This results in acceleration, rotation, and magneticfield changes between the position sensor 7 and the sensors 8.

The processing unit 8 is also configured to detect obstacle by usingdata provided by the said sensors 11. The processing unit 9 might beconfigured to detect the changes between the data provided by theposition sensor 7 and the sensors 8. The sensors 11 might comprise atorque sensor for each of the wheels 3. The sensors 11 might comprise ageographical position system.

As illustrated on FIG. 16, the position sensor 7′ might put inside thechassis 2′, while being secured to the connecting module 5, for examplevia an arm. This makes it possible to move the position sensor 7′, suchas a magnetometer, away from the cutting motors and thus from theelectromagnetic noise which disturbs the magnetometer. This assemblyamplifies the linear acceleration sensed by the inertial unit, whichmakes the shock detection more effective.

FIG. 17 illustrates a cutting head R1 for a brush cutter, edge trimmeror the like. The cutting head 1 comprising a front cutting module R2.The front cutting module R2 comprises:

-   -   a comb R3 having longitudinally extending teeth R4;    -   a plurality of three motorized disk R5, R6, R7 aligned        transversely.

The longitudinal direction is the displacement direction of the cuttinghead. The transversal direction is the direction which is orthogonal tothe displacement direction in a plane which is parallel to the ground onwhich the cutting head is displaced.

Each disk of the plurality of motorized disk is rotatably mounted on thecomb R3 around a rotation axis. Each disk of said plurality of motorizeddisk is driven in rotation by a rotor of a motor (not shown), said motorhaving a stator secured on the front cutting module R2. Each disksupports a plurality of articulated blades adapted to extend radiallyrelative to the rotation axis of the disk under the effect of thecentrifugal force.

FIG. 17 illustrates three blades R8, R9, R10, fixed on disk R5. Thewidth R13 of the comb R3 is greater than three times the cut diameterR14 of the cut area R15. The cut area R15 of a blade, when moved by thecentrifugal force, is a disk represented by a grayed area. The distanceR16 between the axis of two consecutive motorized disks such asmotorized disks R5 and 6R is between 2 and 2.4 times the radius of thecut area.

The comb R3 has interposed teeth R17 extending longitudinally along acentral axis perpendicular to the axes of consecutive motorized disks R5and R6. The comb R3 has interposed teeth R18 extending longitudinallyalong a central axis perpendicular to the axes of consecutive motorizeddisks R6 and R7. The comb R3 has teeth R19 whose ends extend in anarcuate area R20. The comb R3 has a conformation comprising a passageR21 forming a path R22 for discharging grass cut by the blades 8, 9, 10.

The cutting head R1 has a conformation comprising a passage R21. Thepassage R21 forms a path R22 for discharging grass cut by thearticulated blades R8, R9, R10 (see FIG. 1). The passage 21 is a meansfor cutting the grass in a reverse direction, i.e, in a displacement ofthe cutting head following the arrow 22.

FIG. 18 is a schematic representation of a scooter R23 according to anembodiment of the invention. The scooter R23 is coupled to the cuttingR1 head by means of coupling means R22.

FIG. 19 is a schematic representation of a segway R24 according to anembodiment of the invention. The segway 24 is coupled to the cuttinghead 1 by means of coupling means 22.

FIG. 20 is a schematic representation of a robot R25 according to anembodiment of the invention. The robot R25 includes the cutting head R1and is, in the embodiment illustrated, an autonomous robot.

FIG. 21 is a schematic representation of another scooter R26 accordingto an embodiment of the invention. FIG. 22 is a schematic representationof another embodiment R100 of a cutting head according to the invention.The cutting head R100 comprising a front cutting module R200.

The front cutting module R200 comprises:

-   -   a comb R300 having longitudinally extending teeth R400;    -   a plurality of three motorized disk R500, R600, R700 aligned        transversely.

The front cutting module R200 might be can be adjusted in height withrespect to a device R800 connected to the robot chassis. For thispurpose, the device R800 comprises a switch R802. When the switch R802is possessed at the top, it causes a height adjustment upwards byoperating a motor R804 lifting in one direction. This has the effect ofwinding a cable R806 on a pulley R808 connected to the rotor portion ofthe motor R804 and to lift the block R200. This block is in slideconnection with two guides R810 and R812. By operating the switch R802downwards, the opposite occurs.

Of course, the invention is not limited to the examples which have justbeen described and numerous adjustments can be made to these exampleswithout departing from the scope of the invention. In addition, thevarious features, forms, variants and embodiments of the invention canbe combined with one another in various combinations insofar as they arenot incompatible or exclusive of one another. Other variations to thedisclosed embodiments can be understood and effected by those skilled inthe art in practicing the claimed invention, from a study of thedrawings, the disclosure, and the appended claims.

What is claimed is:
 1. A robot comprising a first axle and a secondaxle, a first axle housing comprising a first transversal axle connectedto a rigid structure by a hinge having a first degree of freedom inrotation around a first axis which is vertical and a second degree offreedom in rotation around a second axis which is perpendicular to thefirst axis and to a first transversal axis, and the axle of the firsttransversal axle being equipped on either side with a motor, each motorhaving a stator part configured to be fixed to the first transversalaxle and a rotor part configured to be rotatably mounted to a respectivewheel to provide steering and propulsion functions.
 2. The robotaccording to claim 1, wherein the robot is further arranged to receiveelectronic controls configured to control each of the motors fitted tothe axle housing.
 3. The robot according to claim 2, wherein theelectronic controls are configured to drive each motor independently. 4.The robot according to claim 1, wherein the hinge is placed on a centerof the transversal axis.
 5. The robot according to claim 1, wherein itscenter of gravity is located between the four wheels.
 6. The robotaccording to claim 1, wherein the chassis is a shell that goes downbetween the two axles to lower the center of gravity.
 7. The robotaccording to claim 1, wherein the rigid structure is a shell.
 8. Therobot according to claim 1, comprising a unique battery.
 9. The robotaccording to claim 1, comprising a frontal cutting module locatedbetween two wheels, and two other steering wheels.
 10. The robotaccording to claim 1, further comprising four driving wheels.
 11. Therobot according to claim 2, wherein the electronic controls areconfigured to implement a robot moving strategy towards a predetermineddestination point by minimization of a distance to a predetermineddestination point, the strategy being locally random.
 12. The robotaccording to claim 2, comprising an obstacle detector.
 13. The robotaccording to claim 12, wherein the obstacle detector is configured todetect an obstacle by a combination of two or more of the followingparameters: counter electromotive force of one of the motors;differential of inertial components for detection of acceleration and/oracceleration variation; angular sensor of steering wheels; geographicallocalization.
 14. The robot according to claim 11, wherein theelectronic controls are configured to invert a direction of movement ofthe robot when an obstacle is detected.
 15. The robot according to claim11, comprising a frontal cutting module place between two wheels, andwherein, in the event that the obstacle detected is on a side of thecutting tool, the electronic controls are configured to stop the robotand to select a steering direction to circumvent the obstacle beforeinverting a direction of movement.
 16. The robot according to claim 1,comprising an angular sensor of an angle formed by the transverse axlerelative to the frame, the angular sensor comprising a flag fixed inrotation with the first axis and a rangefinder to measure a distancebetween the flag and a fixed point of the rigid structure.
 17. The robotaccording to claim 1, comprising a stop circumscribing in spacedisplacements of the rear axle.
 18. The robot according to claim 17,wherein the stop comprises a plate of rectangular shape defining a mainplane and a center of the rectangular shape.
 19. The robot according toclaim 18, wherein a plane orthogonal to the main plane and extending ina longitudinal direction of the plate and passing through the center ofthe rectangle is a plane of symmetry of the stop.
 20. The robotaccording to claim 18, wherein a plane orthogonal to the main plane andextending in a direction transverse to a longitudinal direction of theplate and passing through the center of the rectangle is a plane ofsymmetry of the stop.
 21. The robot according to claim 18, wherein fourscrew passages are formed at corners of a rectangle centered on thecenter of the plate.
 22. The robot according to claim 18, wherein fourdamper passages are formed in the plate at corners of a rectanglecentered on the center of the plate.
 23. The robot according to claim18, wherein the stop is one of four stops distributed symmetrically withrespect to two planes of symmetry of the stops.
 24. The robot accordingto claim 23, wherein at least one of the stops has a right-angledtriangle section whose right angle is disposed at one end of therectangle forming the plate, one side of the right angle being orientedin the longitudinal direction of the plate, the other side the rightangle being directed in the direction of a longitudinal planeperpendicular to the main plane.
 25. The robot according to claim 24,wherein in a vertical section transverse to the longitudinal directionof the plate, the plate is hollowed out on a lower central portion toform a “H” which upper left and right interior angles are provided withfillets.